Merge pull request #104 from flexiblepower/development_thijl

Development thijl
Added communication integration tests
General cleanup of unused method parameter
Added check in concentrator for possible null Price
Update coretestsuite
Merge branch 'development' of github.com:flexiblepower/powermatcher into Testing
Merge pull request #105 from flexiblepower/development_tom

fixed #67
Merge branch 'development' of https://github.com/flexiblepower/powermatcher into development_thijl